b
Explanation:
I'm apologize if I'm wrong
Answer:
Target Heart Rate
Explanation:
Target heart rate is generally expressed as a percentage (usually between 50 percent and 85 percent) of your maximum safe heart rate. The maximum rate is based on your age, as subtracted from 220. So for a 50-year-old, maximum heart rate is 220 minus 50, or 170 beats per minute.
Medulla Oblongata
The lower part of the brain stem ( the part connected to the spinal cord) controls most of the functions you dont think about.<span />